1. Field of the Invention
The present invention relates generally to a record player, and is directed more particularly to a tone arm control apparatus of a record player by which a tone arm is electrically controlled by a knob operation to locate the tone arm at a desired position on a record disc, for example, a third program or music recorded on the record disc.
2. Description of the Prior Art
In the prior art, there is proposed a tone arm driving device of record player in which a driving means such as a driving motor is provided on the horizontal rotary shaft of the tone arm. With such the tone arm driving device, since the frictional force for a tone arm lifter and so on is changed due to variation of the stylus pressure of a cartridge, the speed of the tone arm becomes high or low as compared with a predetermined moving speed. Therefore, a gear or the like is employed to reduce the driving force of the motor to drive the tone arm horizontally. Due to the provision of the above element, vibrations are generated from the motor and gear so that when the movement of tone arm is stopped by a hand, a large force is generated in the horizontal rotary shaft and, as a result, the bearings and so on are damaged.
Further, due to the fact that the moving speed of the tone arm is constant, when a predetermined appointment position (where the stylus is to be initially located) is near the inner-most record groove of a record disc, the time period for the tone arm to move to the appointment position becomes long and hence it is considered very late that the tone arm arrives at the appointment position from its initial position.
In the prior art, it is also known that, in order to control the resonance of a pick-up caused by the distortion or deformation of a record disc, the tone arm is controlled electrically. A driving motor is provided on a weight. The weight serves to add a stylus pressure, while the motor automatically adjusts the stylus pressure and accordingly improves the property of the tone arm, and simplify the operational property.
In that case, a motor is required to drive the tone arm, which results in that the rotor of the motor is added to the tone arm. Therefore, the effective mass of the tone arm increases, and accordingly the construction becomes complicated, the size becomes large and the load for the vertical and horizontal bearings becomes great.